The Tasek Bera is a lowland freshwater inundated riparian system at its climax phase due to intensive denudation, extensive stream capture, low stream orders, the formation of benthic peat, the absence of distinct river channels, the occurrence of reverse flows especially during the northeast monsoon, and inundations of the order of 1–5 m reaching the crowns of the swamp-forest trees (Sections 2.1 and 2.2). This riparian swamp system has a history of about 4.500 years B.P. with a gradual colonisation of hydrophytes, and a sudden change from a lowland river depositing silt to a riparian swamp depositing autochthonous peat (Section 2.2). This transition from a river to a riparian swamp appears to be of biogenic origin, to the damming effects of Pandanus. The Tasek Bera is a remnant of a once extensively distributed forested riparian system in tropical southeast Asia, known as ‘Rassau’ rivers because the flowing waters are lined by Pandanus (Corner 1940). Such riparian swamps form 10–20% of the lowland landscape and, together with coastal, peat and mangrove swamps, have been transformed and utilized by man for wet-rice cultivation which has prevailed in this region for at least 2.000 years. In view of the scarcity of riparian swamps such as the Tasek Bera, it is necessary to understand their role at the land-water interface especially in regulating water discharge through the rivers, its purification and the recovery of nutrients, and the importance of the inundation or floods for essential ecological processes such as enhancing biological production and stimulating reproduction of riparian fishes (e.g. cyprinids and Sclero-pages ).
KeywordsBiomass Migration Phosphorus Phytoplankton Respiration
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